PubMed Health⌕ Search

Biomedical subjects

F B Meyer

Publications and source records attributed to F B Meyer.

At least 37 records · Page 2Linked to original sources
PubMed2000

Adenovirus-mediated gene transfer to human cerebral arteries.

Gene therapy is being investigated as a putative treatment option for cardiovascular diseases, including cerebral vasospasm. Because there is presently no information regarding gene transfer to human cerebral arteries, the principal objective of this study was to characterize adenovirus-mediated expression and function of recombinant endothelial nitric oxide synthase (eNOS) gene in human pial arteries. Pial arteries (outer diameter 500 to 1,000 microm) were isolated from 30 patients undergoing temporal lobectomy for intractable seizures and were studied using histologic staining, histochemistry, electron microscopy, and isometric force recording. Gene transfer experiments were performed ex vivo using adenoviral vectors encoding genes for bovine eNOS (AdCMVeNOS) and Escherichia coli beta-galactosidase (AdCMVLacZ). In transduced arteries, studied 24 hours after exposure to vectors, expression of recombinant beta-galactosidase and eNOS was detected by histochemistry, localizing mainly to the adventitia (n = 4). Immunoelectron microscopy localized recombinant eNOS in adventitial fibroblasts. During contractions to U46619, bradykinin-induced relaxations were significantly augmented in AdCMVeNOS-transduced rings compared with control and AdCMVLacZ-transduced rings (P < 0.01; n = 6). The NOS inhibitor L-nitroarginine methylester (L-NAME) caused significantly greater contraction in AdCMVeNOS-transduced rings (P < 0.001; n = 4) and inhibited bradykinin-induced relaxations in control and transduced rings (P < 0.001; n = 6). The current findings suggest that in AdCMVeNOS-transduced human pial arteries, expression of recombinant eNOS occurs mainly in adventitial fibroblasts where it augments relaxations to NO-dependent agonists such as bradykinin. Findings from the current study might be beneficial in future clinical applications of gene therapy for the treatment or prevention of cerebral vasospasm.

Adenoviridae↗
PubMed2000

Long-term outcomes for surgically resected craniopharyngiomas.

OBJECTIVE: This retrospective study critically analyzed the long-term functional outcomes and tumor recurrence rates for surgically treated craniopharyngiomas. METHODS: This study used an outcome classification system that included functioning vision, independent versus dependent living, Karnofsky Performance Scale scores, academic levels, work status, and psychological status. Tumor recurrence rates were analyzed with respect to the extent of surgical resection and adjunctive radiotherapy. RESULTS: For 121 patients, with a mean follow-up period of 10 years, the overall "good outcome" rate was 60.3%. Factors associated with poor outcomes included lethargy at presentation, visual deterioration, papilledema, tumor calcification, hydrocephalus, and tumor adhesiveness at surgery. Gross total resection was associated with good outcomes (P = 0.017) and decreased risk of recurrence (P = 0.024). Subtotal resection was associated with increased risk of tumor recurrence (P = 0.0235). The highest risk of recurrence was in the subtotal resection/no radiation group (P = 0.0001). There were no differences in outcomes or recurrence rates between pediatric and adult patients. There were also no differences in outcomes or recurrence rates between papillary and adamantinous tumors. Approximately one-third of patients exhibited morbid obesity, and permanent diabetes insipidus was observed for 25 patients. CONCLUSION: A rigorous evaluation of outcomes for tumors such as craniopharyngiomas must consider not only the extent of resection, as judged by postoperative imaging, but also the long-term physical, intellectual, and psychological functioning of the patients.

Adolescent↗
PubMed2000

Clinically silent corticotroph tumors of the pituitary gland.

OBJECTIVE: To determine the clinical presentation, imaging characteristics, microscopic and ultrastructural characteristics, and treatment outcomes of patients with clinically silent pituitary corticotroph adenomas. METHODS: All silent corticotroph adenomas diagnosed at the Mayo Clinic during the years 1975 through 1997 were selected from the files of the Mayo Tissue Registry. RESULTS: We studied 23 cases, occurring in 16 male and 7 female patients (age range, 11-79 yr; mean age, 48 yr), who presented with headaches (50%), visual field defects (61%), extraocular muscle paresis (13%), hypopituitarism (26%), and galactorrhea/amenorrhea (43%/29% of the female patients). No patients exhibited clinical hypercortisolism. All tumors were macroadenomas (2.4+/-0.8 cm; range, 1.5-4.0 cm) and exhibited suprasellar extension in 87% of the cases and hemorrhage, necrosis, and/or cystic changes in 61%. All tumors stained were variably periodic acid-Schiff-, adrenocorticotropic hormone-, and beta-endorphin-positive, particularly Subtype I lesions. Ultrastructural classification was performed in 19 cases. In a comparison of Subtype I and II tumors, differences were observed with respect to sex (male/female, 1.4:1 versus 6:1), preoperative hyperprolactinemia (5 of 16 versus 0 of 6 cases), preoperative hypopituitarism (9 of 16 versus 5 of 7 cases), radiographic or gross invasion (7 of 16 versus 5 of 7 cases), and partial or total postoperative pituitary failure (6 of 16 versus 6 of 6 cases). The overall median postoperative follow-up period was 4.9 years (range, 0.3-16.6 yr); 54% of the patients had persistent or recurrent tumors. CONCLUSION: Clinically silent corticotroph adenomas behave in an aggressive manner and are characterized by the following: lack of clinical signs or symptoms of Cushing's syndrome and normal cortisol levels; no or only minor elevations of serum adrenocorticotropic hormone levels; macroadenomas with hemorrhagic infarction; and presentation dominated by mass effect symptoms. The high persistence/recurrence rate underscores the need for long-term follow-up.

Adenoma↗
PubMed2000

Factors predictive of the outcome of frontal lobe epilepsy surgery.

PURPOSE: To identify factors that predict the outcome in seizure control after frontal lobe epilepsy surgery (FLES). FLES is the second most frequent type of epilepsy surgery, but the results are generally not as good as those after anterior temporal lobectomy. METHODS: Our cohort consisted of 68 consecutive patients whose first epilepsy surgery involving the frontal lobe occurred between 1987 and 1994. Clinical history and results of imaging and electroencephalographic studies were reviewed in detail. Excellent outcome was defined as being seizure free or having only nondisabling seizures at last follow up. RESULTS: Forty of the 68 patients (58.8%) had an excellent outcome; none of the patients with a history of childhood febrile seizures had an excellent outcome, whereas outcome was excellent in 63% of those without that history (p </= 0.01). The other significant presurgical factor was the presence of a potentially epileptogenic lesion in the frontal lobe on neuroimaging (excellent outcome in 72% when present versus 41% when absent, p </= 0.001). The only significant postsurgical factor was early postoperative seizure control in the first year (excellent outcome in 96% with early control versus 25% without, p </= 0.01). CONCLUSIONS: History of childhood febrile seizures is a poor prognostic factor in FLES patients. It may suggest that the structural basis of all or some of the patients' intractable seizures is mesial temporal sclerosis. On the other hand, neuroimaging detection of a potentially epileptogenic frontal lobe lesion and early postoperative seizure control are associated with subsequent excellent outcome.

Adult↗
PubMed2000

Redefined duplex ultrasonographic criteria for diagnosis of carotid artery stenosis.

OBJECTIVE: To evaluate duplex ultrasonographic criteria for the determination of 50% or more and 70% or more stenosis of the diameter of the internal carotid artery based on conventional angiography in order to align ultrasonographic diagnostic categories with current clinical management schemes. PATIENTS AND METHODS: Between January 1, 1995, and June 30, 1999, 915 patients underwent both carotid duplex ultrasonography and cerebral angiography within 30 days at Mayo Clinic, Rochester, Minn. Of these patients, 294 were excluded from this study because of occlusion of one or both of the internal carotid arteries or atypical flow characteristics. In the remaining 621 patients (61 % male, 39% female; mean age, 67.7 years [range, 14-88 years]), 1218 vessels were available for correlation. Several Doppler ultrasonographic velocity variables were compared with the angiographic findings by use of receiver operating characteristic curve analysis. The primary end point was verification of optimal ultrasonographic criteria to diagnose 70% or more internal carotid artery stenosis. The secondary end point was establishment of threshold values to detect stenosis of 50% or more. RESULTS: At angiography, 382 patients had internal carotid arteries with 70% or more stenosis. Peak systolic and end diastolic velocities of the internal carotid artery and internal carotid artery:common carotid artery peak systolic velocity ratios were measured. For an internal carotid artery stenosis of 70% or more, a peak systolic velocity of 230 cm/s or more resulted in a sensitivity of 86.4%, a specificity of 90.1%, a positive predictive value of 82.7%, a negative predictive value of 92.3%, and an accuracy of 88.8%. An end diastolic velocity of 70 cm/s or more and an internal carotid artery:common carotid artery ratio of 3.2 or more yielded similar values. For an internal carotid artery stenosis of 50% or more, a peak systolic velocity of 130 cm/s or more resulted in a sensitivity of 92.1 %, a specificity of 89.5%, a positive predictive value of 90.3%, a negative predictive value of 91.3%, and an overall accuracy of 90.8%. An internal carotid artery:common carotid artery ratio of 1.6 or more yielded similar values. CONCLUSION: In our ultrasonography laboratory, a carotid artery stenosis of 70% or more (for which carotid endarterectomy is typically recommended in symptomatic patients) is diagnosed reliably with the following duplex ultrasonographic criteria: a peak systolic velocity of 230 cm/s or more, an end diastolic velocity of 70 cm/s or more, or an internal carotid artery:common carotid artery ratio of 3.2 or more.

Adolescent↗
PubMed2000

Surgical treatment of nonatherosclerotic lesions of the extracranial carotid artery.

Nonatherosclerotic disorders of the extracranial carotid artery, such as dissections, aneurysms, and carotid body tumors, are diverse in their causes, presentations, and modes of treatment. The surgical treatment of these lesions often will require a higher exposure of the extracranial carotid than is typical for a carotid endarterectomy. The prevention of perioperative ischemic injury assumes a major role in determining the surgical strategy for treating these lesions. This article offers a brief description of several of these disorders, a review of the general surgical approach to the high cervical artery, and a brief description of lesion-specific surgical techniques.

Aneurysm↗
PubMed2000

Adrenocorticotropic hormone-dependent Cushing's syndrome: sensitivity and specificity of inferior petrosal sinus sampling.

BACKGROUND AND PURPOSE: Determining the cause of Cushing's syndrome can be difficult. Bilateral inferior petrosal sinus (IPS) sampling after ovine corticotropin-releasing hormone (oCRH) stimulation is an established technique for the differentiation of pituitary from nonpituitary sources of adrenocorticotropic hormone (ACTH) production. The purpose of this study was to review our experience to determine the sensitivity and specificity of bilateral IPS sampling. METHODS: Between January 1990 and February 1997, 92 patients underwent 94 IPS sampling procedures. Indications for these patients with Cushing's syndrome included no discrete lesion on MR images or CT scans, a discrete lesion present on images but equivocal peripheral ACTH sampling after oCRH stimulation, and persistent Cushing's syndrome after trans-sphenoidal surgery. RESULTS: IPS sampling yielded six false-negative results and one false-positive result, manifesting an overall sensitivity of 92.2% and a specificity of 90.0% for detection of a pituitary source of ACTH after oCRH stimulation. Microadenoma lateralization by IPS sampling after oCRH stimulation agreed with the surgical location in 70.0% of the patients. The technical success rate of initial (presampling) bilateral IPS catheterization was 93.6%. Two serious complications occurred and consisted of a venous subarachnoid hemorrhage and a lower extremity deep venous thrombosis. CONCLUSION: Bilateral IPS sampling after oCRH stimulation is helpful in the evaluation of ACTH-dependent Cushing's syndrome. False-negative results, however, suggest that the possibility of a pituitary source must still be considered when no response to oCRH is documented. Interpetrosal ACTH gradient alone is not sufficient to lateralize the tumor reliably.

Adolescent↗
PubMed1999

Subtraction SPECT co-registered to MRI improves postictal SPECT localization of seizure foci.

OBJECTIVE: To determine whether the detection of focal hypoperfusion by subtraction SPECT co-registered to MRI (SISCOM) improves the sensitivity and specificity of postictal SPECT in intractable partial epilepsy. BACKGROUND: Postictal SPECT injections are easier to perform than are ictal injections, but the images are more difficult to interpret and have been reported to have lower sensitivity and specificity. METHODS: Thirty-five consecutive intractable partial epilepsy patients who had postictal SPECT studies were evaluated. The following sets of SPECT images were separately interpreted by three blinded reviewers and classified as either localizing to 1 of 16 possible sites in the brain or as nonlocalizing: unsubtracted postictal and interictal images for conventional side-by-side comparison, SISCOM images of hyperperfusion, SISCOM images of hypoperfusion, and both sets of SISCOM hyperperfusion and hypoperfusion images (combined SISCOM evaluation). RESULTS: Significantly higher proportions of the hyperperfusion SISCOM images (65.7%), the hypoperfusion SISCOM images (74.3%), and the combined SISCOM evaluation (82.9%) were localizing than were the conventional method of side-by-side comparison of unsubtracted images (31.4%; p < 0.0001). Concordance with the discharge diagnosis was higher for the combined SISCOM evaluation than it was for either the hyperperfusion or the hypoperfusion SISCOM images alone (both p < 0.05). For the hypoperfusion SISCOM and the combined SISCOM evaluations, concordance of the localization with the site of epilepsy surgery was associated with a greater probability of an excellent outcome than were nonconcordant/nonlocalizing images (both p < 0.05). CONCLUSION: The use of SISCOM to detect focal cerebral hypoperfusion, in addition to focal hyperperfusion, improves the sensitivity and specificity of postictal SPECT in intractable partial epilepsy.

Adolescent↗
PubMed1999

Effects of glucose and PaO2 modulation on cortical intracellular acidosis, NADH redox state, and infarction in the ischemic penumbra.

BACKGROUND AND PURPOSE: During focal cerebral ischemia, the ischemic penumbra or border-zone regions of moderate cortical blood flow reductions have a heterogeneous development of intracellular cortical acidosis. This experiment tested the hypotheses that (1) this acidosis is secondary to glucose utilization and (2) this intracellular acidosis leads to recruitment of potentially salvageable tissue into infarction. METHODS: Brain pHi, regional cortical blood flow, and NADH redox state were measured by in vivo fluorescent imaging, and infarct volume was assessed by triphenyltetrazolium chloride histology. Thirty fasted rabbits divided into 6 groups of 5 each were subjected to 4 hours of permanent focal ischemia in the presence of hypoglycemia ( approximately 2.8 mmol/L), moderate hyperglycemia ( approximately 11 mmol/L), and severe hyperglycemia (>28 mmol/L) under either normoxia or moderate hypoxia (PaO2 approximately 50 mm Hg). RESULTS: Preischemic hyperglycemia led to a more pronounced intracellular acidosis and retardation of NADH regeneration than in the hypoglycemia groups under both normoxia and moderate hypoxia in the ischemic penumbra. For example, 4 hours after ischemia, brain pHi in the severe hyperglycemia/normoxia group measured 6.46, compared with 6.84 in the hypoglycemia/normoxia group (P<0.01), and NADH fluorescence measured 173% compared with 114%. Infarct volume in the severe hyperglycemia/normoxia group measured 35.1+/-6.9% of total hemispheric volume, compared with 13.5+/-4.2% in the hypoglycemia/normoxia group (P<0.01). CONCLUSIONS: Hyperglycemia significantly worsened both cortical intracellular brain acidosis and mitochondrial function in the ischemic penumbra. This supports the hypothesis that the evolution of acidosis in the ischemic penumbra is related to glucose utilization. Furthermore, the observation that hypoglycemia significantly decreased infarct size supports the postulate that cortical acidosis leads to recruitment of ischemic penumbra into infarction.

Acidosis↗
PubMed1999

A comparative study of the effects of two nitric oxide synthase inhibitors and two nitric oxide donors on temporary focal cerebral ischemia in the Wistar rat.

OBJECT: A critical review of the literature indicates that the effects of nitric oxide synthase (NOS) inhibitors on focal cerebral ischemia are contradictory. In this experiment the authors methodically examined the dose-dependent effects of two NOS inhibitors and two NO donors on cortical infarction volume in an animal model of temporary focal cerebral ischemia simulating potential ischemia during neurovascular interventions. METHODS: Ninety-two Wistar rats underwent 3 hours of combined left middle cerebral artery and bilateral common carotid artery occlusion after having been anesthetized with 1% halothane. A nonselective NOS inhibitor, N(G)-nitro-L-arginine-methyl-ester (L-NAME), and two NO donors, 3-morpholinosydnonimine hydrochloride and NOC-18, DETA/NO, (Z)-1-[2(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-i um-1,2-diolate, were administered intravenously 30 minutes before ischemia was induced. A selective neuronal NOS inhibitor, 7-nitroindazole (7-NI), was administered intraperitoneally in dimethyl sulfoxide (DMSO) 60 minutes before ischemia was induced. Two ischemic control groups, to which either saline or DMSO was administered, were also included in this study. Seventy-two hours after flow restoration, the animals were perfused with tetrazolium chloride for histological evaluation. Cortical infarction volume was significantly reduced by 71% in the group treated with 1 mg/kg L-NAME when compared with the saline-treated ischemic control group (27.1+/-37 mm3 compared with 92.5+/-26 mm3, p < 0.05). The NOS inhibitor 7-NI significantly reduced cortical infarction volume by 70% and by 92% at doses of 10 and 100 mg/kg: 35.2+/-32 mm3 (p < 0.05) and 9+/-13 mm3 (p < 0.005), respectively, when compared with the DMSO-treated ischemic control group (119+/-43 mm3). There was no significant difference between the saline-treated and DMSO-treated ischemic control groups. Treatment with NO donors did not significantly alter cortical infarction volume. CONCLUSIONS: These results support an important role for NO in ischemic neurotoxicity and indicate that neuronal NOS inhibition may be valuable in reducing cortical injury in patients suffering temporary focal cerebral ischemia during neurovascular procedures.

Animals↗
PubMed1999

Central nervous system histoplasmosis mimicking a brain tumor: difficulties in diagnosis and treatment.

Neurologic involvement occurs in 10% to 20% of patients with disseminated histoplasmosis. We describe a 20-year-old woman who had headache and diplopia but no evidence of systemic infection. Magnetic resonance imaging showed an enhancing mass in the thalamomesencephalic and third ventricular region. After subtotal resection of what was presumed to be a glioma, the patient had symptoms and signs of meningitis. Subsequent pathological review demonstrated noncaseating granulomas, and serologic tests and cultures confirmed the diagnosis of histoplasmosis. Initiation of antifungal therapy and removal of an infected shunt system resulted in clinical improvement. Clinicians should maintain a high index of suspicion in patients who are from any area endemic for histoplasmosis.

Adult↗
PubMed1999

Venous subarachnoid hemorrhage after inferior petrosal sinus sampling for adrenocorticotropic hormone.

Neurologic complications associated with inferior petrosal sinus sampling for adrenocorticotropic hormone in the diagnosis of Cushing syndrome are rare. Previously reported complications include brain stem infarction and pontine hemorrhage. We report a case of venous subarachnoid hemorrhage with subsequent acute obstructive hydrocephalus occurring during inferior petrosal sinus sampling for Cushing syndrome.

Adrenocorticotropic Hormone↗
PubMed1999

Progressive hippocampal atrophy in chronic intractable temporal lobe epilepsy.

We report on a 28-year-old man with long-standing intractable complex partial and secondary generalized seizures, whose magnetic resonance imaging scans 4 years apart documented progressive decrease in the left hippocampal volume. Left anterior temporal lobectomy with amygdalohippocampectomy rendered the patient seizure free at 12 months' follow-up. The findings demonstrate that patients with uncontrolled temporal lobe seizures may develop progressive atrophy of the hippocampus, in the absence of status epilepticus.

Adult↗
PubMed1999

Carotid artery tandem lesions: frequency of angiographic detection and consequences for endarterectomy.

BACKGROUND AND PURPOSE: Several prospective trials have shown that ischemic stroke can be prevented by performing an endarterectomy in patients with high-grade carotid stenosis. Our purpose was to ascertain the frequency of carotid artery tandem lesions and to determine whether their presence alters the surgeon's decision to perform an endarterectomy. METHODS: We retrospectively reviewed the cerebral angiograms obtained between January 1994 and June 1996 in 853 patients with carotid occlusive disease. Studies were analyzed for the presence of internal carotid artery (ICA) stenosis as well as for tandem lesions (defined as > or = 50% diameter stenosis) within the common carotid artery, carotid siphon, or proximal intracranial arteries. The frequency of intracranial saccular aneurysms was determined. RESULTS: Six hundred seventy-two of the 853 patients had a carotid bifurcation stenosis of 70% or greater or underwent an endarterectomy. Of these, a carotid siphon stenosis of 50% or greater was noted in 65 patients (9.7%) and was ipsilateral to an ICA stenosis in 37 patients (5.5%). A common carotid stenosis was present in 29 patients (4.3%), ipsilateral to an ICA stenosis in 14 patients (2.1%). A stenosis of 50% or greater within the proximal intracranial circulation was present in 28 patients (4.2%), ipsilateral to an ICA stenosis in 15 patients (2.2 %). Four patients had tandem stenoses at more than one site. Tandem stenoses in the siphon or intracranial segments were noted in 13.5% with a bifurcation stenosis and in 8.8% of those with no bifurcation stenosis. Endarterectomy was performed in 48 of the 66 patients with tandem stenotic lesions. CONCLUSION: The presence of a tandem lesion infrequently alters the surgeon's decision to perform an endarterectomy. However, the importance of detecting tandem stenoses cannot be underestimated, since they may have important implications for long-term medical management in symptomatic patients.

Aged↗
PubMed1999

Assessment of functional MR imaging in neurosurgical planning.

BACKGROUND AND PURPOSE: Presurgical sensorimotor mapping with functional MR imaging is gaining acceptance in clinical practice; however, to our knowledge, its therapeutic efficacy has not been assessed in a sizable group of patients. Our goal was to identify how preoperative sensorimotor functional studies were used to guide the treatment of neuro-oncologic and epilepsy surgery patients. METHODS: We retrospectively reviewed the medical records of 46 patients who had undergone preoperative sensorimotor functional MR imaging to document how often and in what ways the imaging studies had influenced their management. Clinical management decisions were grouped into three categories: for assessing the feasibility of surgical resection, for surgical planning, and for selecting patients for invasive functional mapping procedures. RESULTS: Functional MR imaging studies successfully identified the functional central sulcus ipsilateral to the abnormality in 32 of the 46 patients, and these 32 patients are the focus of this report. In epilepsy surgery candidates, the functional MR imaging results were used to determine in part the feasibility of a proposed surgical resection in 70% of patients, to aid in surgical planning in 43%, and to select patients for invasive surgical functional mapping in 52%. In tumor patients, the functional MR imaging results were used to determine in part the feasibility of surgical resection in 55%, to aid in surgical planning in 22%, and to select patients for invasive surgical functional mapping in 78%. Overall, functional MR imaging studies were used in one or more of the three clinical decision-making categories in 89% of tumor patients and 91% of epilepsy surgery patients. CONCLUSION: Preoperative functional MR imaging is useful to clinicians at three key stages in the preoperative clinical management paradigm of a substantial percentage of patients who are being considered for resective tumor or epilepsy surgery.

Adolescent↗
PubMed1998

Comparison of North American Symptomatic Carotid Endarterectomy Trial and population-based outcomes for carotid endarterectomy.

PURPOSE: The North American Symptomatic Carotid Endarterectomy Trial (NASCET) advocated the use of carotid endarterectomy (CEA) for transient ischemic attacks (TIAs), nondisabling strokes, and ipsilateral high-grade stenosis in highly selected patients. Whether similar results are achieved when CEA is applied to an entire geographically defined population is unknown but important if the NASCET recommendations are to be applied broadly to all community patients. METHODS: To determine the survival rate to ipsilateral stroke after CEA for all symptomatic patients in a defined population, we reviewed the medical records of all patients residing in Olmsted County, Minn. (approximately 100,000), who underwent a CEA for TIA or nondisabling stroke between 1970 and 1995. Their outcomes were compared with the NASCET results. RESULTS: In the community of Olmsted County, 297 patients (108 women and 189 men) underwent 322 CEAs during the study period. TIAs or nondisabling stroke was the indication in 254 patients (86%), whereas the remaining 14% had asymptomatic stenosis. After CEA for symptomatic lesions, survival rate free of ipsilateral stroke was 97% at 2 years, 93% at 5 years, and 92% at 10 years. These results are similar to the NASCET survival rates free of ipsilateral stroke at 2 years (91%). However, the 30-day postoperative stroke rate for patients older than 80 years was significantly higher than that for patients younger than 80 years. CONCLUSIONS: When the NASCET results are compared with a population-based experience in which all symptomatic patients undergoing CEA were analyzed, the early outcomes were similar. Our population-based data also document the remarkably durable long-term results of CEA in preventing stroke and present another benchmark for carotid stent angioplasty.

Age Factors↗
PubMed1998

"Rhabdoid" meningioma: an aggressive variant.

It is has been suggested that rhabdoid morphology is associated with a poor prognosis, regardless of tumor histogenesis. We report a series of 15 meningiomas with rhabdoid features. Nine patients had undergone multiple resections. In six, the rhabdoid component was histologically apparent only in recurrences. Rhabdoid morphology was defined as sheets of loosely cohesive cells with eccentric nuclei and hyaline, paranuclear inclusions. Ultrastructurally, the latter consisted of whorls of intermediate filaments often entrapping lysosomes or other organelles. Meningothelial features included whorl formation and nuclear pseudoinclusions, immunohistochemical coexpression of vimentin and epithelial membrane antigen, and the ultrastructural finding of interdigitating cell membranes and intercellular junctions. At the histologic level, a conventional meningioma component was noted in most tumors; only four lesions were entirely rhabdoid. Histologic malignancy (brain invasion or anaplasia) was observed in nine cases, another two tumors being considered malignant on the basis of extracranial metastasis. In the majority, increased cell proliferation was evidenced by a high mitotic rate or MIB-1 LI. At last follow-up, 13 patients (87%) had experienced at least one recurrence and 8 (53%) were dead of disease. Median time to death was 5.8 years after initial surgery and 3.1 years after the first appearance of rhabdoid morphology. Our findings corroborate those from a smaller series recently reported by Kepes et al. on the same entity (Kepes JJ, Moral LA, Wilkinson SB, Abdullah A, Llena JF. Rhabdoid transformation of tumor cells in meningiomas: A histologic indication of increased proliferative activity. Report of four cases. Am J Surg Pathol 1998;22:231-8). They further suggest that rhabdoid meningiomas are highly aggressive tumors and that the rhabdoid phenotype represents a marker of malignant transformation in meningiomas.

Adolescent↗